<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>监听器应用-距离</title>
</head>
<body>
    <script src="../js/vue.js"></script>
    <div id="app">
       <p>{{km}}</p>
       <p>{{m}}</p>
    </div>
     
    <script>
        var vm = new Vue({
          el:"#app",  
          data: { 
            km:0,
            m:0 
        },
        methods: {
            kmtom:function(val){
                this.m = this.km * 1000;
            },
            mtokm: function(val){
                this.km = this.m / 1000;
            }
        },
        watch: {
            km: 'kmtom',
            m: 'mtokm'
        } 
    }) 
    </script>
</body>
</html>
